PS2:Open PS2 Loader (OPL)

Open PS2 Loader (OPL) is a homebrew application loader that loads PS2 games and applications from digital devices. It works by loading special software to both the Emotion Engine (EE) and the I/O CPU, which interfere in the game normal behavior. The IOPCORE, which runs in the I/O(PS1) CPU is in charge of replacing the CDVDMAN module amongst others. Its main purpose is the CDVDMAN module replacement, since this one is in charge of disc tray I/O. The replacement module is coded to load of a digital device (USB, network, HDD, MX4SIO, iLink). For all intents and purposes, the game believes it is loaded from the disc drive.

The EE program (known as EECORE) is in charge of hooking up several syscalls, and interfering in certain operations that would remove the IOPCORE (such as rebooting the I/O CPU, or uploading an IOPRP image to the I/O CPU).

Compatibility Issues

Every game is different. The PS2 library has more than 4,000 games, all of which are coded with different versions of the Sony SDK, on different years, by different companies. To worsen things, the IOP core has to maintain the smallest footprint possible due to the limitation of 2MB of RAM. The only PS2 models with extra RAM are the development tools and the PSX DESR, so the RAM issue will be a problem for 99% of the PS2 models around the world.

RAM consumption is also tied to the device that is hosting the game image. The most demanding devices are SMB network and USB. And the ones which consume the least of IOP RAM are MX4SIO and internal HDD.

Later slims (SCPH-75xxx+) had slightly worse compatibility. Fortunately, on 2023 OPL got support to operate the XPARAM module, which is in charge of changing the compatibility configurations of the DECKARD emulator. Ensuring compatibility with the ~286 games listed on the PS2TV internal compatibility list (the newest one), no matter which slim version and region you're using.

USB & MX4SIO SD Card Setup

If you are using OPL 1.1.0 or older the USB or SD card must be formatted as FAT32. OPL 1.2.0 and newer also support exFAT which means games larger than 4Gb will not need to be split.

On the root of a USB storage device, create folders named "DVD" and "CD". Your game backups will go in the CD and DVD folders depending on what disc type they had originally come on, with CD games being 700MB or less in size. If you have games larger than 4GB, use the "Splitting Games" section on this page to deal with them.

Using SD cards via MX4SIO

New in OPL 1.1.0 is support for MX4SIO Block Devices which provides a faster way to load backups than USB while maintaining the same compatibility and file structure.

To enable SD card Block Device support in OPL:

1. Go to Settings and change BDM Start Mode to Manual (Press X, press down once then press X) (Auto seems to freeze often on release 1.1.0)
2. Go to the right to Block Devices, press X, go to MX4SIO, press X to enable, go down to OK press X. (Do not press O to go back it will forget the settings!)

   Optional: change default menu to "BDM Games", go down to OK, press X

3. Select Save changes on the menu screen
4. Press O to go to games list
5. Go left to select BDM then press X to Start Device
6. Select your game and use OPL as normal!

Splitting Games

Games larger than 4GB on USB will need to be split.

1. Download a splitting tool such as USBExtreme, and extract the contents to your Desktop and launch it.
2. Mount the ISO that you wish to split by right-clicking it and selecting "Open with..." > Windows Explorer. If you are not using Windows 8 or 10, you will need to use a tool such as Daemon Tools Lite to mount it. Take note of the drive letter that is assigned.
3. Navigate to where you extracted USBExtreme.exe and open it.
4. Click on the drop down menu under "CD/DVD ROM Drive" and select the drive letter of the mounted ISO.
5. Click on the drop down menu under "Media Type" and select "DVD".
6. Click on the drop down menu under "Hard Drive" and select the drive letter that corresponds with your USB storage device.
7. In the "Game Name" field enter the name of the game you will be splitting.
8. Click the "Start" button, then click "Yes" to start the install. The program will begin splitting the game and will copy the split files to the root of your USB storage device. The games will be playable from the default location.